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Study of Bs → K(∗)+− decays in the PQCD factorization approach with the lattice QCD input

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arXiv 2020年

作者： Jin, Su-Ping Hu, Xue-Qing Xiao, Zhen-Jun Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, we studied systematically the semileptonic decays Bs → K(∗)+− with l− = (e−,µ−,τ−) by using the perturbative QCD (PQCD) and the "PQCD+Lattice" factorization approach, respectively. We first evaluated all relevant form factors Fi(q2) in the low q2 region using the PQCD approach, and we also take the available Lattice QCD results at the end point qmax2 as additional input to improve the extrapolation of the form factors to the high q2 region. We calculated the branching ratios and other twelve kinds of physical observables: AFB(l), PL, FLK∗ and the angular observables Pi and Pj′. From our studies, we find the following points: (a) for Bs → Kl+l− decays, the PQCD and "PQCD+Lattice" predictions for branching ratios (BRs) B(Bs → Kl+l−), the ratios of the BRs RKeµ,µτ and the longitudinal polarization asymmetry of the leptons PL agree well within errors;(b) the "PQCD+Lattice" prediction B(Bs → K∗µ+µ−) = (2.58+0−0..6960)×10−8 does agree well with the LHCb measured value (2.9 ± 1.1) × 10−8;(c) for the ratios RKeµ∗ and RKµτ∗, the PQCD and "PQCD+Latatice" predictions agree very well and have a small error less than 10% due to the cancellation of the theoretical uncertainties in the ratios of the branching ratios;(d) for the angular observables P1,2,3 and P4′,5,6,8 , our theoretical predictions for each lepton l− are consistent within errors;(e) the theoretical predictions of the angular observables P3 and P6′,8 are less than 10−2 in absolute value, but the magnitude of P1,2 and P4′,5 are larger than 0.2;and (f) the PQCD and "PQCD+Lattice" predictions of the binned values of all considered observables in the two q2-bins [0.1 − 0.98]GeV2 and [1.1 − 6]GeV2 generally agree with each other and also be consistent with the LCSR results within errors. We believe that above predictions could be measured by future LHCb and Belle-II experiments. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum theory

A novel class of energy-preserving Runge-Kutta methods for the Korteweg-de Vries equation

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arXiv 2021年

作者： Chen, Yue Gong, Yuezheng Hong, Qi Wang, Chunwu Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing211106 China MIIT Nanjing211106 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing210023 China

In this paper, we present a quadratic auxiliary variable approach to develop a new class of energy-preserving Runge-Kutta methods for the Korteweg-de Vries equation. The quadratic auxiliary variable approach is first proposed to reformulate the original model into an equivalent system, which transforms the energy conservation law of the Korteweg-de Vries equation into two quadratic invariants of the reformulated system. Then the symplectic Runge-Kutta methods are directly employed for the reformulated model to arrive at a new kind of time semi-discrete schemes for the original problem. Under the consistent initial condition, the proposed methods are rigorously proved to maintain the original energy conservation law of the Korteweg-de Vries equation. In addition, the Fourier pseudo-spectral method is used for spatial discretization, resulting in fully discrete energy-preserving schemes. To implement the proposed methods effectively, we present a very efficient iterative technique, which not only greatly saves the calculation cost, but also achieves the purpose of practically preserving structure. Ample numerical results are addressed to confirm the expected order of accuracy, conservative property and efficiency of the proposed algorithms. Copyright © 2021, The Authors. All rights reserved.

关键词： Runge Kutta methods

Investigating the excited ω 0 c states through c K and c K decay channels

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arXiv 2017年

作者： Huang, Hongxia Ping, Jialun Wang, Fan Dept. of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Physics Nanjing University Nanjing210093 China

Inspired by the five newly observed ω 0 c states by the LHCb detector, we study the ω 0 c states as the Swave molecular pentaquarks with I = 0, JP = 1 2 , 3 2 , and 5 2 by solving the RGM equation in the framework of chiral quark model. Both the energies and the decay widths are obtained in this work. Our results suggest that c(3119)0 can be explained as an Swave resonance state of D with JP = 1 2 , and the decay channels are the Swave cK and cK . Other reported ω 0 c states cannot be obtained in our present calculation. Another ω 0 c state with much higher mass 3533 MeV with JP = 5 2 is also obtained. In addition, the calculation is extended to the 0 b states, similar results as that of ω 0 c are obtained. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

Exploring dynamical phase transitions in the XY chain through a linear quench: Early and long-term perspectives

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Physical Review A 2024年第4期110卷 042209页

作者： Kaiyuan Cao Hongsheng Hou Peiqing Tong School of Physics Hangzhou Normal University Hangzhou 311121 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 China

We investigate the nonequilibrium dynamics induced by a finite-time linear quench in the XY chain. Initially, we examine the dynamical quantum phase transition (DQPT-LE), characterized by the nonanalytic behavior of the Loschmidt amplitude. We find distinct behaviors of DQPT-LEs during and following the ramp. Following the ramp, the ramp crossing the critical point hc is the sufficient condition for the occurrence of DQPT-LE, but it is not during the ramp. Through adiabatic-impulse-adiabatic (AIA) approximation analysis, we establish that adequate distancing from the critical point is crucial for DQPT-LE manifestation during the ramp, elucidating the absence of DQPT-LE as the ramp gets faster. Additionally, we explore another type of dynamical phase transition (DQPT-OP), describing the long-term relaxation behavior of the order parameter. Our finding indicates that the asymptotic behavior of the time-dependent part induced by the linear quench is equivalent to that following a sudden quench, i.e., the time-dependent part exhibits power-law decays of ∼t−3/2 and ∼t−1/2 for the ramp to the commensurate and incommensurate phases, respectively. Moreover, we also delve into the steady part, which showcases nonanalytic singularities at the critical point.

关键词： Dynamical phase transitions Nonequilibrium statistical mechanics XY model

Search for doubly heavy dibaryons in the quark delocalization color screening model

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Physical Review C 2022年第2期105卷 025201-025201页

作者： Zhuocheng Xia Saijun Fan Xinmei Zhu Hongxia Huang Jialun Ping Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Department of Physics Yangzhou University Yangzhou 225009 People's Republic of China

We perform a systemical investigation of the low-lying doubly heavy dibaryon systems with strange S=0, isospin I=0, 1, 2, and the angular momentum J=0, 1, 2, 3 in the quark delocalization color screening model. We find the effect of channel-coupling cannot be neglected in the study of the multi-quark systems. Several bound systems are obtained. They are the doubly charm dibaryon systems with IJ=00, IJ=01, and IJ=02, and the corresponding energies are 4590, 4720, and 4764 MeV, respectively; and the doubly bottom dibaryon systems with IJ=00, IJ=02, and IJ=13, and the corresponding energies are 11219, 11416, and 11633 MeV, respectively. Besides, six resonance states are obtained, which are IJ=00NΞcc and NΞbb with resonance masses of 4730 and 11411 MeV respectively, IJ=11NΞcc* and NΞbb* with resonance masses of 4775 and 11432 MeV respectively, and IJ=12ΣcΣc* and ΣbΣb* with resonance masses of 4935 and 11626 MeV respectively. All these heavy dibaryons are worth searching for in experiments, although it will be a challenging work.

关键词： Cluster models Particle interactions Quark model Heavy baryons

Pc-like pentaquarks in a hidden strange sector

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Physical Review D 2018年第9期97卷 094019-094019页

作者： Hongxia Huang Xinmei Zhu Jialun Ping Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Department of Physics Yangzhou University Yangzhou 225009 People’s Republic of China

Analogous to the work of hidden charm molecular pentaquarks, we study possible hidden strange molecular pentaquarks composed of Σ (or Σ*) and K (or K*) in the framework of a quark delocalization color screening model. Our results suggest that the ΣK, ΣK*, and Σ*K* with IJP=1212− and ΣK*, Σ*K, and Σ*K* with IJP=1232− are all resonance states by coupling the open channels. The molecular pentaquark Σ*K with quantum numbers IJP=1232− can be seen as a strange partner of the LHCb Pc(4380) state. The possibility of identifying the resonances as nucleon resonances is proposed.

关键词： Hadron-hadron interactions Quark model

Semileptonic decays Bc → (ηc, J/ψ)lν¯l in the "PQCD + Lattice" approach

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arXiv 2019年

作者： Hu, Xue-Qing Jin, Su-Ping Xiao, Zhen-Jun Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, we studied the semileptonic decays Bc− → (ηc,J/ψ)l−ν¯l by employing the PQCD factorization approach, using the newly defined distribution amplitudes of the Bc meson and the new kind of parametrization for extrapolation of the form factors, and also taking into account the lattice QCD results about the relevant form factors at several points. We found the following main results: (a) the PQCD predictions for the branching ratios of Bc → (ηc,J/ψ)lν¯ decays will become a little smaller by about (5 − 16)% when the lattice input are taken into account in the extrapolation of the relevant form factors;(b) the PQCD predictions for the ratio Rηc,J/ψ and the longitudinal polarization Pτ are Rηc = 0.34±0.01,RJ/ψ = 0.28±0.01, Pτ(ηc) = 0.37±0.01 and Pτ(J/ψ) = −0.55±0.01;and (c) after the inclusion of the lattice input the theoretical predictions changed slightly: Rηc = 0.31 ± 0.01, RJ/ψ = 0.27 ± 0.01, Pτ(ηc) = 0.36 ± 0.01 and Pτ(J/ψ) = −0.53 ± 0.01. The theoretical predictions for RJ/ψ agree with the measured one within errors, and other predictions could be tested in the near future LHCb experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

Perturbative QCD factorization of ργ⋆→π

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Physical Review D 2014年第7期90卷 076001-076001页

作者： Shan Cheng Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China

In this paper, we firstly verify that the factorization hypothesis is valid for the exclusive process ργ⋆→π at the next-to-leading order (NLO) with the collinear factorization approach, and then extend this proof to the case of the kT factorization approach. We particularly show that at the NLO level, the soft divergences in the full quark level calculation could be canceled completely as for the πγ⋆→π process where only the pseudoscalar π meson is involved, and the remaining collinear divergences can be absorbed into the NLO hadron wave functions. The full amplitudes can be factorized as the convolution of the NLO wave functions and the infrared-finite hard kernels with these factorization approaches. We also write out the NLO meson distribution amplitudes in the form of nonlocal matrix elements.

关键词： YANG-Baxter equation QUARKS WAVE functions MESONS PARTICLE physics

Reanalysis of the most strange dibaryon within constituent quark models

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Physical Review C 2020年第3期101卷 034004-034004页

作者： Hongxia Huang Xinmei Zhu Jialun Ping Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Department of Physics Yangzhou University Yangzhou 225009 People's Republic of China

The most strange dibaryon ΩΩ with quantum numbers S=−6, I=0, and JP=0+,1−,2+,3− is reanalyzed in the framework of a quark delocalization color screening model (QDCSM) and chiral quark model (ChQM). The ΩΩ dibaryon with JP=0+ is bound, and the one with other quantum numbers JP=1−,2+,3− are all unbound in our calculation. The low-energy scattering phase shifts, the scattering length, and the effective range of the ΩΩ dibaryon with JP=0+ also support the existence of such strange dibaryon. This dibaryon is showed to be a shallow bound state in QDCSM, while the binding energy becomes much larger in the ChQM by including the effect of the hidden color channels coupling. And the scalar nonet meson exchange in the ChQM also provides more attraction for the ΩΩ system. Experimental search for such most strange dibaryon will provide much information for understanding the hadron-hadron interactions in different quark models.

关键词： Nucleon-nucleon interactions Quark model